Force indicating device



Dec. 15, 1970 B. GRABOVAC vFORCE INDICATING DEVICE ,2.Sheets-Sheet 1Filed July 11,1968

Dec, 15, 1970 a. GRABOVAC 3,546,933

I FORCE INDIGATING DEVICE Filed July 11, 1968 2 Sheets-Sheet 2 Joye/4201" ,Bo-S/PO @rabouac 3,546,933 FORCE INDICATING DEVICE Bosko Grabovac,P.O. Box 1685, Altadena, Calif. 91001 Filed July 11, 1968, Ser. No.744,007 Int. Cl. G01l 5/24 U.S. Cl. 73-141 8 Claims ABSTRACT OF THEDISCLOSURE A device arranged between the lever arm or handle of a handtool and the hand of an operator that will signal the operator when apredetermined force is exerted, by his hand, through the device and ontothe tool handle. The device includes an elongate hand-engaging body, atool handle engaging pad carried by the body between the ends thereofand an adjustable signalling means within and carried by the body.

Throughout industry, where screw type fastening means are employed,there is an ever-increasing requirement and/ or demand that the forcesapplied to such fasteners be a predetermined force, sufficient toestablish the holding or fastening effect desired, but not so great asto cause distortion and/or to set up undesired and detrimental stress inthe fastening means and in the work with which said means are related.

To satisfy the above requirement the prior art has provided torquewrenches, that is, hand tools which have means incorporated therein tolimit the amount of torque or the forces that can be appliedtherethrough and onto a screw fastening means with which they areapplied, or

having means incorporated therein which indicate the force appliedthrough the tool onto the fastening means or which signal or in othersuitable manners indicate when the desired predetermined force to beapplied to the fastening means is reached.

Those torque wrenches or tools provided by the prior art varyconsiderably in details of construction and mode of operation, but arealike or similar to each other in the following respects. First, theyare large, heavy and cumbersome. Secondly, they are designed andconstructed for special situations and are such that their use ismaterially limited by the environment in which the fasteners upon whichthey are to be used are found. Third, there exists a limited number ofsuch tools, suitable for use in a limited number of special situations,as compared with the infinite number of situations where screw typefastening means are employed, with the result that there is only arelatively small number of situations where proper torquing ortightening of such fastening means can be effected with the toolspresently available. Fourth, such tools are extremely costly as comparedwith conventional tools, and, fifth, they are extremely delicate and aresuch that they must be handled and treated with extreme care.

While special adapters and attachments have been provided for the torquewrenches provided by the prior art, to extend their usefulness and adaptthem for other and different application than for those specialapplications for which they were designed, such adapters and attachmentshave, for the most part, proven to be complicated, costly andtroublesome means to employ. Further, they frequently create suchundesirable drag and uneven distribution of forces applied therethroughthat the accuracy and intended function of the torque wrenches isrendered undependable or useless.

In those situations where torque wrenches cannot be advantageouslyemployed, tightening of screw-type fastening means is effected withconventional hand tools and the forces applied is left to the sense oftouch and United States Patent 0 3,546,933 Patented Dec. 15, 1970judgment of the operator in whose hands the tools rest.

An object of my invention is to provide a means or device by or withwhich an operator, when using conventional hand tools for tighteningscrew-type fasteners and the like, can accurately and dependably apply apredetermined force onto and through the fastening means and/or work.

Another object of this invention is to provide a means or device of thecharacter referred to which is engageable between the hand of anoperator and a hand tool and which is such that when a predeterminedforce is applied onto the hand tool by the operator, such fact orcondition is effectively communicated to theloperator through his senseof touch, hearing and/or sight.

Yet another object of this invention is to provide a means or device ofthe general character referred to which is such that the forces appliedby the operators hand through the subject means or device, is applied toa related hand tool at the predetermined location or point on the tooland so that the mechanical advantage afforded by the tool ispredetermined and the force applied to the fastening means or the workby the hand tool, upon the application of force by the operator throughthe subject means or device and onto the tool, can be easily andconveniently determined and limited.

It is an object of this invention to provide a means or device of thecharacter referred to which is small, light and compact and is such thatit can be advantageously arranged and positioned between an operatorshand and a hand tool in substantially all situations where sufficientspaces is afforded to permit engagement of the operators hand on thehand tool.

It is yet another object of my invention to provide a means or device ofthe character referred to including an elongate body section carrying atool-engaging, forceapplying pad, an elongate, small, narrowhand-engaging section adapted to extend transverse and to be engaged bythe palm and/ or fingers of an operators hand and movably or shiftablycarried by the body section and adjustable or variable force indicatingmeans in and between the sections to limit and/or indicate when apredetermined force is applied therebetween.

Still another object of the invention is to provide another form ofdevice of the character referred to includ ing an elongate body adaptedto extend transverse of and to be engaged by the palm and/or fingers ofan operators hand, a force-applying pad to engage a hand tool andadjustable or variable force indicating means in the body and connectedwith the pad to signal or indicate when a predetermined force is appliedthrough the body and pad onto the tool.

- Yet another object of the present invention is to provide a device ofthe character referred to which involves a small number of easy andeconomical to manufacture and assemble parts and a device which isrugged and durable and a device which is highly accurate, effective anddependable in operation.

The foregoing and other objects and features of my invention will befully understood from the following detailed description of typicalpreferred forms and applica tions of my invention, throughout whichdescription reference is made to the accompanying drawings, in which:

FIG. 1 is an isometric view of a force indicator device for hand tools;

FIG. 2 is a perspective view showing the device illustrated in FIG. 1 inuse, between the handle of a tool and an operators hand;

FIG. 3 is an enlarged, longitudinal, sectional view of my new deviceshowing it related to the handle of a tool;

FIG. 4 is a sectional view taken as indicated by line 44 on FIG. 3;

FIG. is a sectional view taken as indicated by line 55 on FIG. 3;

FIG. 6 is a sectional view taken as indicated by line 66 on FIG. 3;

FIG. 7 is a sectional view taken as indicated by line 77 on FIG. 3;

FIG. 8 is an enlarged detailed sectional view of a portion of thestructure illustrated in FIG. 3 and showing parts in another or actuatedposition;

FIG. 9 is an elevational view of a second form of my invention;

FIG. 10 is a longitudinal sectional view of the structure shown in FIG.9;

FIG. 11 is a sectional view taken substantially as indicated by line11-11 on FIG. 10;

FIG. 12 is a longitudinal sectional view of a third form of myinvention;

FIG. 13 is a sectional view taken as indicated by line 13-13 on FIG. 12;and,

FIG. 14 is a longitudinal sectional view of another and fourth form ofthe invention.

Referring to the drawings and to the preferred form of the invention,shown in FIGS. 1 through 7, the force indicating device A includes abody B, a tool engaging pad P carried by the body, a hand engaging bar Hmovably or pivotally carried by the body and pressure responsivesignalling means S carried by the body and operatively related to thebar H.

In addition to the foregoing, the device A is provided with adjustingmeans C to vary and adjust the signalling means S.

The body B is an elongate tubular part and, referring to FIG. 3 of thedrawings, is shown extending horizontally, as having opening front andrear ends 10 and 11 and longitudinally extending, laterally spaced innerand outer sides 12 and 13 (shown at the top and bottom sides of the bodyin FIG. 3 of the drawings).

The body is shown as being cylindrical in cross-section and as having acylindrical bore 14. In practice, the body B can be of any othersuitable cross-sectional configuration.

The tool engaging pad P is a saddle-like part fixed to the inner side 12of the body at a point spaced between the front and rear ends thereof,to project laterally inwardly from the body. The pad P is provided witha central, longitudinally extending, laterally inwardly opening,substantially V-shaped channel 15 and/or a transversely extending,laterally inwardly opening substantially V-shaped channel 16, whichchannel or channels define laterally inwardly divergent tool engagingsurfaces adapted to straddle a hand engaging part of a hand tool and tothereby centralize the body with the said hand engaging part of the handtool and to prevent lateral shifting and displacement of the device fromengagement with the hand tool.

In FIGS. 2, 3 and 5 of the drawings, the hand tool is shown as a socketwrench W having an elongate lever arm with an outer, cylindrical,knurled handle or hand engaging part 21. The body B is shown arranged inspaced parallel relationship to the tool handle 21 with said handleengaged and seated in the longitudinal channel 15 of the pad.

The channel 15 and/or the channel 16 in the pad P is, or are, ofsufiicient longitudinal extent to provide a desired, limited amount oflongitudinal stability between the device A and the tool handle 21 andyet sufiiciently short in longitudinal extent so that forces transmittedthrough the device A and onto the tool handle 21 are concentrated at apredetermined point longitudinally of the tool 21 (within allowabletolerances).

In practice and as will be explained in the following, the tool handle21 can be suitably marked or scribed, as at 22, to establish and providea suitable reference for the proper positioning of the device A, withthe tool,

when the device A is employed in combination therewith.

It will be apparent that the device A can be arranged to extendtransverse the tool handle 21 with said tool handle engaged in thechannel 16 of the pad when desired or circumstances require.

It will be further apparent that when the tool handle 21 is engaged inone or the other of the channels 15 or 16 the other of said channelsprovides a window-like relieved portion to facilitate viewing the mark22 on the tool handle 21 and proper positioning of the device on saidtool handle.

The hand engaging bar H that I provide is an elongate member, havingfront and rear ends 25 and 26 and is arranged in spaced relationshipwith and along the outer side 13 of the body B.

The front end of the bar H is pivotally connected to the front endportion of the body B by pivot means M and carries a socket element ofthe signalling means S at its rear end.

In the case illustrated the bar H is an elongate, laterally inwardlyopening, U-shaped or channel shaped part with a laterally outwardlydisposed longitudinally extending base portion 27 which occurs along theouter side of the body and laterally inwardly projecting longitudinalside portions or walls 28 which occur at opposite sides of the body B.

The bar extends a limited predetermined distance longitudinally beyondthe outer end 11 of the body B and is provided with an end wall 29 whichoverlies the end 11 and carries the socket element of the means Sreferred to above and which will hereinafter be described.

The pivot means M includes a pair of axially alligned screw fasteners 30with suitable bearing shoulders rotatably engaged in aligned openings 31in the front end portions of the side walls 28 of the bar H and engagedand fixed in the adjacent opposite sides of the body B, as clearlyillustrated in FIG. 4 of the drawings.

The bar H is of limited longitudinal and cross-sectional extent and issuch that it can be easily, conveniently and comfortably engaged acrossthe palm and/ or fingers of an operator in the general manner show inFIG. 2 of the drawings.

In practice and as illustrated, the bar H is preferably normallyarranged with its longitudinal axis longitudinally outwardly divergentrelative to the axis of the body, as illustrated in FIG. 3.

The signalling means S that I provide includes a longitudinallyshiftable plunger 40 in the rear end portion of the body B, a socketpart or member 41 carried by the end wall 29 of the bar H, a sear block42 between the plunger and socket part and a compression spring 43 inthe body and normally yieldingly urging the plunger longitudinallyoutwardly towards the socket part and to maintain the block inpredetermined pressure engagement therebetween.

The plunger 40 is a simple, elongate, cylindrical part slidably engagedin the rear end portion of the body B and is provided with alongitudinally rearwardly opening recess 45 with a flat, axiallyrearwardly disposed bottom 46 and rearwardly and longitudinallyoutwardly divergent sides 47.

In practice, the recess can be of any desired crosssectionalconfiguration, but is preferably square, with two opposite sides thereofextending parallel and the other two sides extending normal to the planein which the bar H swings,

In practice and if desired, suitable retaining means can be provided tomaintain the plunger from being displaced from engagement in the body.In the case illustrated, retaining means comprising an annular, radiallyoutwardly opening recess 48 about the plunger and a radially inwardlyprojecting annular snap ring 49, carried by the body and projecting intothe recess 48, is provided.

The socket part 41 is a simple metal part or any suitable configurationand fixed to the longitudinally forwardly disposed side of the end wallof the bar H in any suitable manner and is provided with alongitudinally forwardly opening recess 50 with a fiat, axiallyforwardly disposed bottom 51 and forwardly and longitudinally outwardlydivergent sides 52.

The recess 50 is normally in axial alignment and in longitudinallyspaced opposing relationship to the recess 45 and is preferably the samein cross-sectional configuration and in the same axial rotative positionas the recess '45.

The scar block 42 is an elongate, normally longitudinally extendingblock corresponding in cross-sectional configuration with the bottoms 46and 51 of the sockets 45 and 50 and having flat, forward and rearends 55and 56 normally establishing flat bearing engagement on the opposingbottoms 46 and 51 of the sockets 45 and 50, as clearly illustrated inFIG. 3 of the drawings.

The spring 43 is a simple, elongate, helical compression spring arrangedin the body B to extend longitudinally therein and has an outer endbearing on the flat inner end of the plunger 40 and is stopped at itsother or front end by suitable means, such as the adjusting means C andso that it exerts a predetermined force or pressure longitudinallyrearwardly through the plunger, block and onto the socket part.

With the signalling means S set forth above, the plunger, block andsocket part remain in that set, axial alignment shown in FIG. 3 of thedrawings until a predetermined lateral inward force is exerted onto thebar H to the socket part 41 and sear block 42, which force exerts aninward turning force onto and through the block which is greater thanthe axial rearward force exerted onto the block by the plunger and thespring. The moment when the noted turning force exceeds the notedrearward force by a predetermined volume, the block tips and turnsinwardly in the manner shown in FIG. 8 of the drawings, against theresistance of the spring.

The plunger 40 is free to move forwardly against the resistance of thespring 43 and so that the construction is not locked and can move in themanner set forth above.

When the means S shifts from its normal position as shown in FIG, 3 toits actuated position shown in FIG. 8, the movement is rapid and sharpand is such that a sharp clicking sound is heard and a shock can be feltwhen the construction bottoms out or stops in its actuated position andthe movement of the bar H relative to the body B can be seen, with theresult that the operator of the tool is signalled and made aware thatthat force necessary to actuate or trigger the means S has been appliedonto and through the device.

It will be apparent that the force necessary to trigger the device isapplied onto the bar H by the application of inward forces on the bar bythe hand of the operator of the device.

The pivotal movement of the bar relative to the body and therefore thelateral inward movement of the socket part relative to the plunger, islimited so that the block is not pivoted a sufiicient extent to move itover-center and to such an extent that it will not be returned to itsnormal, unactuated position by the force of the spring, after the forcewhich caused it to actuate is relieved. In the case illustrated, therear end of the bar is stopped in the manner set forth above and for thereason or purpose stated by the body B, as illustrated in FIG. 8 of thedrawings.

The adjusting means C is shown as including a discshaped spring stop 60in the body B and at the forward end of the spring 43, a plug 61 fixedin the body as by means of the screw fasteners 30 of the means M anaxially movable adjusting bolt 62 threadedly engaged through the plug 61and having a rear end engaging the spring stop 60 and a front endportion, with a head 63 projecting forwardly from and accessible at theforward end of the body, a series of calibrations 64 about the front endportion of the body, an indicator sleeve 65 with a mark 66 thereonthreaded on the forward portion of the bolt and having front and rearportions outward of and within the front portion of the body forward ofthe plug 61 therein and a set screw 68 releasably securing the sleeve 65in fixed position on the bolt.

By advancing or withdrawing the bolt so as to vary the extent to whichthe spring is compressed, the device can be zeroed in or set to actuateupon the exertion of a predetermined base force.

When it is set to actuate at such a base force, the sleeve 65 isadvanced fore or aft on the bolt until the mark 66 thereon is alignedwith a desired calibration 64 on the body and is then locked in positionon the shaft by the set screw 68.

With a means C such as set forth above, it will be apparent that theforce or forces required -to actuate the device are predetermined andset and that adjustment of the forces required to actuate the device canbe easily and conveniently varied as desired or as circumstancesrequire.

In practice, for example, the device can be designed, adjusted and setso that there are ten numbered calibration lines on the body B, spacedcircumferentially so that upon moving the mark 66 on the sleeve 65 fixedon the bolt 62 from one calibration to the other varies the forcerequired to actuate the device ten pounds.

By adjusting and setting the bolt and sleeve so that when the mark is onthe first calibration line a force of ten pounds is required to actuatethe device, the operator can easily and conveniently increase the forceprogressively ten pounds at a time and to as much as pounds by simplymanually turning the sleeve and registering the mark with appropriatecalibration lines.

When the device is used as intended and in combination with a hand tool,the lever arm and mechanical advantage afforded by the hand tool isfirst determined. In this respect, consideration is first given to wherethe device A is most suitably and most likely to be engaged with or onthe hand tool. When this is determined, it may be desirable andadvantageous to provide the hand tool with a reference mark, such as themark 22 on the handle 21 of the wrench W in FIGS. 2 and 3 of thedrawings. Still further, it may be desirable and advantageous to markand indicate the length of the moment arm of the tool, such as isillustrated at 22 on FIG. 3 of the drawings.

With the effective moment arm of the tool established and marked, it iseasy to determine how many pounds of force must be exerted onto andthrough the tool to gain and apply a predetermined force onto the work.

In the case illustrated, if the moment arm of the wrench W, from theaxis of the socket to the mark 22, is ten inches and it is desired toapply 200 pounds of torque onto the fastener with which the wrench isrelated, it is easy to determine that twenty pounds of force should beapplied to the wrench at the mark 22. By setting the device A to actuateat twenty pounds, for example, by setting the mark 66 on calibrationline number 2 and then turning the wrench W with and by means of thedevice A, the application of 200 pounds of force on the fastener can beaccurately accomplished.

In FIGS. 9 through 11 of the drawings, I have shown another or secondform of force indicating device A.

The device A distinguishes from the device A by eliminating the bar Hand by combining the functions and certain of the structural features ofthe bar H, pad P and signalling means S of the first form of theinvention in a novel pad P.

In this second form of the invention, a plunger 40 with a recess 46similar to the plunger 40 in the first form of the invention is slidablyengaged in a tubular body B. The plunger 40, like the plunger 40 isacted upon and urged longitudinally in the body B by a spring 43, undercontrol of adjusting means S in a manner similar to the first form ofthe invention.

In advance of the plunger 40 and fixed within the body B is a stop plugor block 70 with an elongate trans- 7 versely extending semi-circularguide channel 71, which channel opposes the socket 45' in the plunger40'.

The body B is provided with a lateral access opening 72 in axialalignment with the channel 71.

The pad P, like the pad P, is provided with laterally outwardly openingtool engaging channels and 16, but rather than being fixed to the body Bas is the pad P in the first form of the invention, it is provided witha stem 72 which extends through the opening 72 in the body and isslidably engaged or seated in the channel 71 in the stop block 70.

The stem 72 is provided with an annular radially outwardly openinggroove 73 with a straight cylindrical bottom 74 equal in axis extentwith the lateral extent of the bottom 46 of the socket or recess 45 inthe plunger and longitudinally and radially outwardly divergent ends 75.

A sear block 42', similar to the block 42 in the first form of theinvention is arranged between the plunger 40 and the stem with one endseated on the bottom 46 of the recess in the plunger and its other endseated on the bottom 74 of the groove 73 in the stem 72 on the pad.

In the preferred carrying out of the invention the end of the sear block42 engaging the groove in the stem is provided with a rounded channel 76to cooperatively receive and seat about the bottom portion of the groove73.

The device A is designed and constructed so that the pad P is arrangedand positioned substantially centrally or between the ends of the body Band so that the forces exerted onto and through the device and a relatedtool can be most conveniently and effectively distributed andcontrolled.

In operation, the device A functions in a manner similar to the deviceA. When a predetermined force is applied onto and between the body B'and the pad P, the stem 72 is urged transverse the axis of the bodyturning and/ or tipping the sear block 42' against the resistance of thespring 43 and transmitting audible and sensory signals to the operatorof the device.

In the drawings I have illustrated a different form of spring settingand adjusting means C. However, since the particular form andconstruction of the means C can vary widely without departing from thespirit of this invention, I have chosen not to show the means C indetail and will not burden this disclosure with a detailed descriptionthereof. It will suffice to say that the means C' is such that it willperform similar functions and provide the same end results as the meansC in the first form of the invention.

In FIGS. 12 and 13 of the drawings I have shown another or third form ofthe invention. In this third form of the invention the device A includesa body B bar H pad P signalling means S and spring setting and adjustingmeans C In this third form of the invention, the means S rather thaninvolving a scar block as in the first form of the invention (andsecond), involves a cam-type of triggering means including a cam post 80on the bar H remote from the pivot means M which connects the bar to thebody B and which depends into the body. The post 80 is provided with anelongate, vertical, axially forwardly disposed cam surface 81 with acentral lobe defining a forwardly and downwardly disposed concaved seatportion. Arranged within the forward portion of the body is a bell crank82 with a forward vertical leg 83 and an upper leg 84 projectingrearwardly from the upper end of the forward leg. The lower end of theforward leg 83 is pivotally mounted in the body forward of the cam post.The upper leg extends rearwardly past the post and connects with theforward end of a tension spring 85, the rear end of which is connectedwith the means C The bell crank, at the junction of the legs 83 and 84,rotatably carries a roller-type cam follower which follower normallyengages and rests in the seat portion of 8 the cam surface 81. Thespring normally yieldingly urges and maintains the cam follower in theabove-noted unactuated position on the cam surface.

In the third form of the invention, actuation of the signalling means iseffected by downward pressure applied on the bar H and cam post which issuflicient to urge the lobe of the cam surface downwardly past thespring loaded follower. Actuation of the means S like actuation of themeans S, in the first form of the invention, is subject to delicate andaccurate control by a thorough adjustment of the spring and the means Cand is such that the moment the force necessary to elfect actuation isreached, operation of the device is rapid and sharp and provides thoseaudible, sensory and/ or visual signals necessary to inform the operatorof the fact that it has actuated.

The means C in this third form of the invention, like the means C in thefirst form of the invention, is such that it permits adjustment andsetting of the spring 85, as desired and as necessary for carrying outthe invention.

Since the means C can vary widely in form and construction withoutdeparting from the spirit of this invention and since the means Cillustrated is only typical of the type of means that might beadvantageously employed, I will not burden this disclosure with furtherdetailed consideration thereof.

In FIG. 14 of the drawings I have shown a fourth form of my inventionwherein the device A is similar in most respects to the first form ofthe invention, the principal distinction being that this last formemploys a tension spring rather than a compression spring and thosemodifications of the basic structure employed in the first form of theinvention which are necessary to make possible the use of a tensionspring are included.

In this last form of the invention, the element 40 with the sear blocksocket or recess 45 therein is fixed in the body B and is provided witha central, axially extending opening 80. The scar block 42 is providedwith an axially extending stem 81 which extends freely through theopening 80 and which is connected with its related end of the tensionspring 43 The other end of the spring 43 is connected with the adjustingmeans C which means distinguishes from the means C in that it isdesigned in a manner suitable to vary and adjust the tension of thespring 43.

In this fourth form of the invention the end wall 29 of the bar H has afiat portion on which the block 42 normally seats and is provided with ashoulder to engage and tip the block when the bar is urged toward thebody. With this relationship of parts, the socket 41 provided in thefirst form of the invention is formed integrally with the bar.

When the structure shown in FIG. 4 is actuated by the application offorce on the bar H and the force of the tension spring '43, whichnormally maintains the block 42 in its unactuated position, is overcome,the block tips and the bar H moves sharply and rapidly in the samemanner that the block 42 and bar H in the first form of the inventiontip and move.

Finally, in this fourth form of the invention, 1 have shown thecentrally located pad P pivotally mounted on the body B on an axisextending transverse the axis of the body and for the purpose of showingand making it understood that the pad need not be movably fixed to thebody as is shown in the first and third forms of the invention.Pivotally mounting the pad can be extremely advantageous and desirablefor many circumstances since it permits full bearing support of thedevice on a tool handle and assures application of force on the handleat the proper location, even though the device, for any reason, is notin parallel alignment with the handle on a vertical plane.

It is to be understood that in the second form of the invention, thepost on the pad P is free to rotate in the body and that the pad is,therefore, pivotally mounted and free to turn on a vertical axis. Thisfunction allows for extensive misalignment of the device on a horizontalplane without adverse elfect.

While I have not shown a pad pivotally mounted on both horizontal andvertical axes, for instance a structure combining the forms of padmounting means in FIGS. and 13, with their attending functions, it willbe apparent that such a structure could be provided without departingfrom the spirit of this invention.

Having described only typical preferred forms and applications of myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself anymodifications and/ or variations that may appear to those skilled in theart and which fall within the scope of the following claims.

Having described my invention, I claim:

1. A force indicating device adapted to be engaged in the hand of anoperator and to engage a lever arm portion of a hand tool and to signalthe operator when the the force applied by his hand through the deviceand onto the tool reaches a predetermined magnitude, said deviceincluding an elongate body having front and rear ends and inner andouter sides and engageable across the palm and/ or fingers of anoperators hand, with its outer side disposed away from said operatorshand, tool engaging means projecting laterally from the outer side ofthe body at a location substantially intermediate the ends thereofwhereby the force exerted onto and through the body of the operatorshand is resolved at said tool engaging means for transmission onto arelated hand tool and signalling means carried by the body to generateand transmit a signal to the said operator when the force appliedthrough the device and onto a tool reaches a predetermined magnitude,said signalling means including a spring loaded trigger mechanismbetween the body and a movable force-load carrying part.

2. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate bar positioned adjacent the inner side ofthe body to extend in substantially parallel spaced relationshiptherewith and to occur between the body and the operators hand, pivotmeans connecting one end portion of the bar to an adjacent end portionof the body and a part of said trigger mechanism carried by the bar at apoint remote from the pivot means.

3. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate post intermediate the ends of the body andhaving an outer portion projecting outwardly from the outer side of thebody and carrying the tool engaging pad and an inner portion within thebody and carrying a part of said trigger mechanism.

4. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate bar positioned adjacent the inner side ofthe body to extend in substantially parallel spaced relationshiptherewith and to occur between the body and the operators hand, pivotmeans connecting one end portion of the bar to an adjacent end portionof the body and a part of said trigger mechanism carried by the bar at apoint remote from the pivot means, said trigger mechanism including aplunger in the body with an axially opening recess with a flat bottom atone end, said part carried by the bar having a socket with a fiat bottomspaced from and opposing the recess and normally in axial alignmenttherewith, an elongate sear block with flat ends between said plun gerand part with its end opposing and normally in flat engagement on theflat bottoms and a compression spring in the body engaging the other endof the plunger to yieldingly urge the plunger toward the block and saidpart whereby said bearing engagement between the ends of the block andthe flat, opposing bottoms is yieldingly maintained and pivoting of thebar relative to the body is thereby yieldingly prevented.

5. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate bar positioned adjacent the inner side ofthe body to extend in substantially parallel spaced relationshiptherewith and to occur between the body and the operators hand, pivotmeans connecting one end portion of the bar to an adjacent end portionof the body and a part of said trigger mechanism carried by the bar at apoint remote from the pivot means, said part of the trigger mechanismcarried by the bar including an elongate came extending transverse theaxis of the body and having a lobe with a side disposed obliquely to thedirection of pivotal movement of the bar, said trigger mechanism furtherincluding a cam follower shiftably carried by the body and normallyengaging said side of the lobe and spring means normally yieldinglyurging the follower into pressure engagement on the cam to yieldinglyinhibit movement of the cam lobe relative to the follower and therebyyieldingly prevent pivotal movement of the bar relative to the body.

6. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate bar positioned adjacent the inner side ofthe body to extend in substantially parallel spaced relationshiptherewith and to occur between the body and the operators hand, pivotmeans connecting one end portion of the bar to an adjacent end portionof the body and a part of said trigger mechanism carried by the bar at apoint remote from the pivot means, said part of the trigger mechanismcarried by the bar including an elongate cam extending transverse theaxis of the body and having a lobe with a side disposed obliquely to thedirection of pivotal movement of the bar, said trigger mechanism furtherincluding a cam follower shiftably carried by the body and normallyengaging said side of the lobe and spring means normally yieldinglyurging the follower into pressure engagement on the cam to yieldinglyinhibit movement of the cam lobe relative to the follower and therebyyieldingly prevent pivotal movement of the bar relative to the body,said cam follower being carried by a bell crank having one leg pivotallymounted in the body, said spring means including an elongate tensionspring extending longitudinally in the body having one end fixed to theend of the other leg of the bell crank and its other end fixed to alongitudinally shiftable screw actuated adjusting means carried by thebody.

7. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate post intermediate the ends of the body andhaving an outer portion projecting outwardly from the outer side of thebody and carrying the tool engaging means and an inner portion withinthe body and carrying a part of said trigger mechanism, said partcarried by the post extending transverse and intersecting the axis ofthe body and formed with an annular recess with a straight cylindricalbottom and inclined ends, said trigger mechanism further including anelongate plunger slidably engaged in the body with one end spaced fromand opposing the part with the recess and having a socket with a flatbottom in said one end, an elongate sear block arranged centrally withinthe body in parallel relationship therewith and between said part andthe plunger and having a fiat end normally establishing flat bearingengagement on the flat bottom and having a semi-circular channel in itsother end normally establishing uniform seated engagement about theone-half of the straight cylindrical bottom opposing said plunger, and acompression spring in the body engaging the other end of the plunger andnormally yieldingly holding the sear block in alignment and pressureseated engagement with and between the straight and fiat bottoms.

8. A device as set forth in claim 1 wherein said movable force-loadcarrying part is an elongate bar positioned adjacent the inner side ofthe body to extend in substantially parallel spaced relationshiptherewith and to occur between the body and the operators hand, pivot 11means connecting one end portion of the bar to an adjacent end portionof the body and a part of said trigger mechanism carried by the bar at apoint remote from the pivot means, said part of the triggering meanscarried by the bar having a fiat surface normal to and intersecting thecentral axis of the body and a shoulder projecting on the flat surfacespaced from the axis of the body toward said bar, the trigger mechanismfurther including an elongate plug in the body with an end spaced fromand opposing said fiat surface, a central axially opening conical recessin said one end of the plug and a central opening communicating betweenthe bottom of the recess and the other end of the plug, an elongatecylindrical sear block with flat ends arranged in axial alignment withthe body between the said flat surface and the plug and having one endnormally establishing flat bearing engagement on said fiat surface andpositioned adjacent said shoulder and its other end seated in saidconical recess, an elongate stem on said other end projecting freelythrough the said opening and a tension spring in the body and connectedwith and normally yieldingly urging and holding the sear block seated inthe recess in axial alignment with the body.

References Cited CHARLES A. RUEHL, Primary Examiner US. Cl. X.R. 73139

